Answer: 2 cm
Explanation:
Given , for a converging lens
Focal length : 
Height of object : 
Object distabce from lens : 
Using lens formula:
, we get
, where v = image distance from the lens.
On solving aboive equation , we get

Formula of Magnification :
, where h' is the height of image.
Put value of u, v and h in it , we get

Hence, the height of the image is 2 cm.
Car A will have highest speed is 83.3m/s .
<h3>What is speed ? </h3>
The rate of change of position of an object in any direction.
The S.I unit is m/s . Speed is a scalar quantity it defines only magnitude not direction
.
speed = distance /time
In case of Car A ,
We have given distance 150Km in 3 min ,
First we have convert the distance km to m
150×1000m
then conversion of min to sec
38×60sec
speed = 15000/180
speed = 83.3m/sec
In case of Car B
we have given 800m in 150 min
lets convert the time into second
150×60
Speed = 800/150×60
speed = 0.88m/ s
In case of Car C
We have given here distance 250 Km and time in 8 hours
convert km to m
25000
and time into sec
88×60×60
speed = 0.86m/ s
Hence ,Car A has highest speed amongst them .
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C.
Explanation: Because mirrors are lighter, and they are easier than lenses to make perfectly smooth.
The magnitude of vector b is 8.58 Unit.
Since both the vectors a and b are perpendicular to each other, so we can apply the Pythagoras theorem to calculate the magnitude of the vector b.
Applying the Pythagoras theorem
(a-b)^2=a^2+b^2
15^2=12.3^2-b^2
b=8.58 unit
Therefor the magnitude of the vector b is 8.58 unit.
Water was confirmed to be on the sunlit surface of the Moon